Minnesota Ice Thickness Safety: How Thick Is Safe to Walk, Sled or Drive

The Minnesota DNR's guideline is simple to state: stay off ice less than 4 inches thick, and treat 4 inches of new, clear ice as the minimum for walking. Heavier loads need more, and white ice needs double. The harder part is that the DNR also says there is no such thing as 100 percent safe ice, and that is not a disclaimer. It is a description of how lake ice behaves.

The figures below are from the DNR's ice thickness guidelines and ice safety pages, verified in October 2026. Check the current chart each winter, since the DNR's vehicle categories are more detailed than the older charts many people remember.

DNR ice thickness guidelines

For new, clear ice only:

Ice thickness	What it will generally support
Under 4 inches	Stay off
4 inches	Ice fishing and other activity on foot
5 to 7 inches	Snowmobile or small ATV
7 to 8 inches	Side-by-side ATV
9 to 10 inches	Small car or SUV
11 to 12 inches	Medium SUV or small truck
13 inches	Medium truck
16 to 17 inches	Heavy-duty truck
20 inches or more	Heavy-duty truck with a wheelhouse shelter

Double all of these on white ice. White or "snow" ice forms when snow on the surface gets saturated and refreezes. It is full of air and only about half as strong as clear ice. A lake with 3 inches of clear ice under 5 inches of white ice does not have 8 inches of ice in any sense that matters.

If you are towing a wheelhouse, use the bottom row.

Why ice is never completely safe

Thickness is one measurement at one spot. Strength depends on more than that.

• Ice does not freeze evenly. The DNR notes it can be a foot or more thick in one place and an inch or two thick a short distance away.
• Moving water. Current near streams, bridges, culverts, narrows and channels between lakes keeps ice thin all winter. On rivers, the ice on outside bends is usually weaker because of the faster current.
• Aerators. Lakes with winter aeration systems have open water or thin ice around them. Heed the thin-ice signs at the access.
• Snow cover. Snow insulates and slows freezing. Its weight also reduces how much additional load the ice sheet can carry.
• Age. New ice is usually stronger than old ice. Ice that has partly thawed is weaker than its thickness suggests.
• Shorelines. Ice near shore is often weaker than ice farther out, which matters most when you are stepping on and off.
• Pressure ridges and cracks. Big lakes such as Mille Lacs, Upper Red and Lake of the Woods expand and contract with temperature, opening cracks and heaving ridges that can have open water alongside. Wind can shift entire ice sheets early in the season.
• Fish and wildlife. Schools of fish can bring warmer water up from the bottom, and flocks of waterfowl can keep spots thin or open.

The practical conclusion is that no chart replaces checking the ice yourself, repeatedly, where you actually plan to walk or drive.

How to check ice

The DNR describes four tools.

• Ice chisel (spud bar). A heavy steel bar with a blade. Strike the ice ahead of you as you walk at early ice. If it goes through in one or two hits, back up. A chisel is a warning system, not a measurement.
• Ice auger. Hand, electric or gas. Drill, then measure.
• Cordless drill. With a long 5/8-inch wood auger bit, a drill goes through 8 inches of ice in under half a minute. Light enough to carry on every early trip.
• Tape measure. Put it down the hole, hook the bottom edge of the ice and read the thickness. Do not judge by how hard the drilling felt.

Start at the shoreline and check again every so often as you move out, more frequently when the ice is in the 4 to 6 inch range and whenever the surface changes color or texture. Note how much is clear ice and how much is white.

What to carry

The DNR's gear list, in rough order of importance:

1. Flotation. A foam life jacket or a float suit. The DNR calls this possibly the number one item for surviving a fall through the ice. Inflatable life jackets are not recommended in cold conditions because they may not inflate properly.
2. Ice picks. Two handles with spikes, connected by a cord and worn around your neck or through your sleeves where you can reach them instantly. Wet ice offers nothing to grip without them.
3. Whistle. Worn on your jacket. Shouting burns energy you do not have.
4. Chisel or drill and a tape measure.
5. Ice cleats. Falls on glare ice cause plenty of injuries on perfectly thick ice.
6. Phone in a waterproof case, and a personal locator beacon where there is no cell coverage, which describes much of the Arrowhead and the Boundary Waters.
7. Rope. For throwing to someone else.

Also tell someone where you are going and when you will be back.

If you fall through

The shock of cold water makes you gasp and breathe hard. Keep your head above water and get your breathing under control. By the DNR's estimate you have roughly ten minutes of useful movement before your arms and legs stop cooperating. That is enough if you use it.

1. Keep your winter clothes on. They trap air and add flotation and warmth. They will not drag you under.
2. Turn back the way you came. That ice held you a moment ago and is probably the strongest nearby.
3. Get your hands and arms up on the unbroken ice. Drive your ice picks in.
4. Kick your feet hard, as if swimming, to bring your body level with the surface, and pull yourself forward onto the ice.
5. Stay flat and roll away from the hole. Standing up puts your full weight back on weak ice.
6. Get warm and dry immediately. Go to a vehicle, a fish house or indoors. Seek medical attention for moderate or severe hypothermia.

Most people who die after going through the ice drown. They do not die of hypothermia. That is why flotation and picks sit at the top of the list.

If someone else falls in

Do not run to the edge of the hole; that produces two victims. The DNR's sequence is preach, reach, throw, row, go. Call 911 first. Shout encouragement and tell them help is coming. If you can reach from shore, extend a rope, a ladder or jumper cables. Otherwise throw a rope or something that floats, and have them tie the rope around themselves before the cold weakens their grip. A light boat pushed across the ice to the hole is the next option. Going out on the ice yourself is the last resort for anyone who is not a trained rescuer.

Vehicles on ice

Driving on ice is routine on Minnesota's big lakes and it is also how the worst accidents happen.

• Use resort-maintained ice roads where they exist, follow the operator's weight limits, and drive slowly.
• Know how you would get out. Many experienced ice drivers keep a window down while moving.
• The DNR advises parking vehicles at least 50 feet apart and moving them every two hours to keep the ice from sagging.
• A DNR tip: drill a hole next to a parked vehicle. If water wells up and overflows the top of the hole, the ice is sinking under the load and it is time to move.
• Avoid driving at night or in snow or fog, when you cannot see cracks, ridges or open water.

If a vehicle breaks through

Get out before it sinks, not after. A vehicle may float for anywhere from a few seconds to a few minutes. Do not wait to see what happens.

• Go out through the side windows. Water pressure can hold doors shut.
• If the windows will not open, break one. The DNR suggests an emergency tool such as a spring-loaded window hammer, kept within reach.
• Once the cabin fills and the vehicle goes under, the odds of escape drop sharply.

For when lakes usually freeze and open, see Minnesota lake ice-out dates and our ice-out tool. For rules, shelters and where to go, see the ice fishing guide.

Bottom line

• Four inches of clear ice to walk, double for white ice, and far more than you would think for a truck and wheelhouse.
• Measure it yourself. The DNR does not, and tracks on the lake are not a measurement.
• Wear picks and flotation every time. If you go in: clothes on, turn around, kick, pull, roll.